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Abstract:

A molecularly imprinted polymer and production process therefor and a
process for selective treatment of poorly degradable and/or toxic
compounds in liquids using the molecularly imprinted polymers. Such
polymers and processes are required for selective removal and/or
degradation of biological, poorly degradable pollutants or toxic
compounds, for example from wastewaters. Consequently, a molecularly
imprinted polymer suitable for the selective treatment of at least one
poorly degradable and/or toxic compound is provided having a polymeric
network which is made up of monomers and has cavities of predetermined
size, wherein the cavities are arranged at predetermined spacings and
have specific binding sites and/or patterns for the poorly degradable
and/or toxic compounds.

Claims:

1. A molecularly imprinted polymer for selective treatment of at least one
of a not easily degradable compound and a toxic compound with a polymer
network constructed from monomers, with cavities of a predetermined size,
the cavities being disposed at predetermined spacings and having at least
one of specific binding sites and specific binding patterns for the
compounds.

2. The polymer according to claim 1wherein the monomers comprise at least
one of carboxylic acids, the amides thereof of carboxylic acids;sulphonic
acids;heteroaromatic bases, weak bases;aliphatic vinyl derivatives,
aromatic vinyl derivatives,isomers of divinylbenzene,
bis(acryloyl)-alkanes,systems based on acrylic acid, systems based on
methacrylic acid;trifunctional acrylate crosslinkers, tetrafunctional
acrylate crosslinkers, and crosslinkers which contain functional groups
which are cross-linked to each other on amide nitrogens via at least one
of aliphatic spacers, aromatic spacers and heteroaromatic spacers.

3. A method for production of a molecularly imprinted polymer for
selective treatment of at least one of a not easily degradable compound
and a toxic compound with a polymer network constructed from monomers,
with cavities of a predetermined size, the cavities being disposed at
predetermined spacings and having at least one of specific binding sites
and specific binding patterns for the compounds,the method comprising
forming a complex of said monomers with at least one of said compounds,
molecule parts thereof and structural analogs thereof in a
solvent,polymerizing the complex with a crosslinker to form a polymer
network with cavities having at least one of a defined size, binding
sites and predetermined patterns which are specific for the compound,
andwashing out the compound.

4. The method according to claim 3wherein forming a complex of said
monomers with at least one of said compounds, molecule parts thereof and
structural analogs thereof comprises forming a complex of at least one of
carboxylic acids, the amides thereof;sulphonic acids;heteroaromatic
bases, weak bases;aliphatic vinyl derivatives, aromatic vinyl
derivatives,systems based on acrylic acid, systems based on methacrylic
acid;trifunctional acrylate crosslinkers, tetrafunctional acrylate
crosslinkers, crosslinkers which contain functional groups which are
cross-linked to each other on amide nitrogens via at least one of
aliphatic spacers, aromatic spacers and heteroaromatic spacers, solvents
which influence parameters;aromatic hydrocarbons;halogenated
hydrocarbons;short-chain alcohols;ether, acetonitrile, tetrahydrofuran,
ethylacetate, acetone, dimethylformamide, dioxane, dimethylsulphoxide;
mixtures of these and mixtures of these with water.

5. A method for selective treatment of at least one of a not easily
degradable compound in liquids and a toxic compound in liquids,the method
including contacting the liquid with at least one polymer which is
molecularly imprinted to at least one of the compound to be treated and
one of the degradation products thereof,and absorbing the at least one of
the compound to be treated and the degradation product thereof in the
molecularly imprinted polymer.

6. The method according to claim 5 further including coupling the
molecularly imprinted polymer to a catalyst material which accelerates
the degradation of the material to be treated.

7. The method according claim 5 further including coupling the molecularly
imprinted polymer to a catalyst selected from coenzyme analogs and
coordinating compounds.

8. The method according to claim 5 further comprising effecting the
degradation by at least one of advanced oxidation processes (AOP), plasma
treatment, photocatalysis, ozonization, ultraviolet irradiation, and
Fenton processes.

9. The method according to claim 5 further including introducing at least
one of titanium, iridium oxide, iron and diamond into the polymers.

10. The method according to claim 8 further including introducing radical
formers in dissolved form and rinsing the radical formers around the
molecularly imprinted polymers.

11. The method according to claim 5 including using at least two different
molecularly imprinted polymers to treat at least two compounds which are
at least one of not easily degradable and toxic.

12-15. (canceled)

16. The method of claim 5 further including removing at least one compound
which is not to be treated from the molecularly imprinted polymer and
subsequently removing the at least one of the compound to be treated and
the degradation product of the compound to be treated from the
molecularly imprinted polymer.

17. A method for at least one of treatment, purification and quality
improvement of at least one of industrial effluents, process effluents of
the chemical industry, process effluents of the pharmaceutical industry,
process effluents of the paper and pulp industry, municipal sewage,
hospital sewage, and effluents of animal husbandry operations, the method
comprising contacting the at least one of industrial effluents, process
effluents of the chemical industry, process effluents of the
pharmaceutical industry, process effluents of the paper and pulp
industry, municipal sewage, hospital sewage, and effluents of animal
husbandry operations with at least one polymer which is molecularly
imprinted to at least one of a compound contained in the at least one of
industrial effluents, process effluents of the chemical industry, process
effluents of the pharmaceutical industry, process effluents of the paper
and pulp industry, municipal sewage, hospital sewage, and effluents of
animal husbandry operations which compound is to be treated and one of
the degradation products thereof, and absorbing the at least one of the
compound to be treated and the degradation product thereof in the
molecularly imprinted polymer.

18. A method for the recovery of at least one of a rare chemical and a
degradation product thereof, the method comprising contacting the at
least one of a rare chemical and a degradation product thereof with at
least one polymer which is molecularly imprinted to the at least one of a
rare chemical and a degradation product thereof, and absorbing the at
least one of a rare chemical and a degradation product thereof in the
molecularly imprinted polymer.

19. A method for at least one of rehabilitation of dangerous waste,
dewatering of waste dumps and rehabilitation of waste dumps, the method
comprising contacting the at least one of dangerous waste and a waste
dump with at least one polymer which is molecularly imprinted to the at
least one of a chemical contained in dangerous waste and a waste dump and
a degradation product of the at least one of a chemical, and absorbing
the at least one of a chemical and a degradation product thereof in the
molecularly imprinted polymer.

Description:

[0001]The present invention relates to a molecularly imprinted polymer and
also to a production method for this purpose and to a method for
selective treatment of not easily degradable and/or toxic compounds in
liquids using the molecularly imprinted polymers. Polymers and methods of
this type are required in order selectively to remove and/or degrade not
easily biodegradable harmful substances or toxic compounds, for example
from sewage.

[0002]The conventional biological purification of sewage in sewage plants
achieves merely insufficient degradation for a number of not easily
biodegradable harmful substances or substances with a specific degree of
persistence. For the purpose of a more extensive elimination of these
materials from sewage or water, inter alia so-called "advanced oxidation"
processes (AOP) are used in addition on a large industrial scale. These
"advanced oxidation" processes use highly reactive radical species,
mainly of the hydroxyl radical with a redox potential of +2.80 V as
oxidant, in order effectively to remove not easily degradable harmful
substances, in fact as far as possible to complete mineralisation of
organic substances into carbon dioxide and water. Because of this high
reactivity, the plurality of organic compounds in the water, i.e. also
the easily degradable, are however attacked. This non-specific attack
then leads, as a function of the type of "advanced oxidation" process
which is used, to an unnecessarily high requirement for oxidants and/or
energy in order to produce the reacting species. As a consequence
thereof, an increase in costs for the technology can be observed and in
addition the underlying process itself can lose its effectiveness.

[0003]It is therefore the object of the present invention to make
available molecularly imprinted polymers and also a method for selective
treatment of not easily degradable and/or toxic compounds in liquids, in
which the selective treatment can be designed more specifically and hence
also more economically.

[0004]This object is achieved by the molecularly imprinted polymer
according to claim 1, the method for production thereof according to
claim 3 and also the method for selective treatment of at least one not
easily degradable and/or toxic compound in liquids according to claim 5.
Advantageous developments of the polymers according to the invention, of
the production methods according to the invention and also of the
treatment method according to the invention are provided in the
respective dependent claims. The method according to the invention for
selective treatment of compounds has a plurality of individual steps
which are intended to be explained subsequently in more detail. Firstly,
the absorption of the compound, i.e. of a material or a specific material
group from the liquid, such as for example water or sewage, into a
molecularly imprinted polymer is effected, as described for example in
claim 1.

[0005]The specific or selective absorption of the target molecule and
similar compounds in the solution is effected, on the one hand, via the
molecule configuration, on the other hand, by defined molecular
recognition mechanisms or specific binding interactions (such as for
example ionic interactions or salt bridges, hydrogen bridge bonds,
hydrophobic interactions and others) with the binding groups at the
cavity surfaces. The absorption of the relevant material or of the
relevant material group can thereby be effected by means of adsorption
(addition) on the surface just as by absorption (incorporation) in the
interior of the material (in general, "sorption" or "sorbing" is
therefore the terminology in the further course).

[0006]Also a combination or successive arrangement is conceivable of
different selective polymer materials for each of the relevant not easily
degradable substances which are present in the relevant sewage.

[0007]Subsequent to the absorption of the target compound in the polymer,
foreign substances which are absorbed jointly in the polymer up to a
certain proportion are washed out with suitable solvents or solvent
mixtures. For application, there can hereby be as solvent water, all
conceivable aqueous solutions and organic solvents, also in a mixture
with each other and also with water or with dissolved organic or
inorganic compounds. This step is not necessarily required but can
possibly be implemented.

[0008]In a further step, the target compounds are released or desorbed as
preferably absorbed compounds or the degradation products thereof with
suitable solvents or solvent mixtures. Here also there can be used for
application water, all conceivable aqueous solutions and organic
solvents, also in mixtures with each other and with water or also with
dissolved organic or inorganic compounds.

[0009]Subsequently, the method according to the invention, in which the
target compounds are thus separated, can be combined or coupled also with
different degradation processes, in particular so-called "advanced
oxidation" processes (AOP=advanced oxidation processes). The respective
harmful substances can be degraded with AOPs of this type.

[0010]A further improvement arises if materials or substances are used
which act catalytically, i.e. accelerating the reaction. These can be
used in addition or also for example coupled to the polymer. Coupling
with the AOPs is likewise possible but also merely the activation energy
for formation of specific oxidation products can be reduced. It is also
possible to control the reaction by means of materials or substances of
this type such that biodegradable products are formed even by partial
oxidation and that hence the oxidant or oxidation method of the AOP can
be used more effectively.

[0011]Furthermore, a combination with a biological disinfection is
advantageous.

[0012]As indicated above already, the washing step for removing the
jointly contained foreign substances and/or the release of the preferably
absorbed material or material group (compound) can be circumvented or
omitted. This is possible if the molecularly imprinted polymer (MIP)
which is laden with the respective material is integrated directly in a
subsequent AOP. The reagents required for the AOP can thereby be injected
or conducted through directly into the polymer material. Even indirect
coupling with catalysts is possible.

[0013]In this case, the compound to be treated selectively is degraded
already directly in the polymer and then the degradation products are
removed again or desorbed from the polymer with suitable solvents or
solvent mixtures, as described above.

[0014]A further possibility or variant of the method resides in binding
the catalytically active centre into the structure of the molecularly
imprinted polymer (MIP) jointly and hence this serves as synthetic enzyme
analogue.

[0015]The catalytic activity of polymers can arise as a result of correct
organisation of the catalytic groups at the molecularly imprinted binding
sites. Structures which produce hydroxyl radicals and/or other
oxygen-containing oxidants can serve as catalytic groups.

[0016]In the case of a previously known established catalytic mechanism
for the degradation of the relevant substances, it is possible to use
transition state analogues (TSAs) in the production of the molecularly
imprinted polymers, as a result of which the transition state of the
relevant degradation reaction is stabilised and the product formation
rate is increased and/or the product formation is controlled either
directly or indirectly.

[0017]Typical degradation reactions can be for example: hydrolysis of
esters, amides, ethers; ring cleavage, aromatic substitution and further
reactions, the transition states of which can be used as transition state
analogues in the production processes.

[0018]A further possibility is the use of coenzyme analogues or
coordinating compounds for catalytic support of the reactions. Also other
catalytic centres can be used.

[0019]The release of the degradation products is then effected after the
degradation reaction, as mentioned above, with suitable solvents or
solvent mixtures.

[0020]With the polymers according to the invention and the method
according to the invention for selective treatment of compounds in
liquids, a large number of advantages can be achieved relative to
conventional methods.

[0021]On the one hand, simple and economical separation of harmful
substances from easily degradable contents or matrix compounds which are
disruptive during the treatment of water by means of AOP is possible.
Also enrichment and concentration of the not easily degradable compounds
or compound classes is possible in order, by means of reduction of the
liquid volume, also to achieve a cost reduction in the AOP or even an
increase in the degradation.

[0022]Furthermore, in the case of the method according to the invention,
only the predetermined selected and relevant not easily degradable or
toxic compounds or compound classes are absorbed specifically from the
liquid, as a result of which an extension of the operating duration of
the selective filter component (polymer) is made possible. The relevant
harmful substances can thereby be degraded also subsequently or
simultaneously, in contrast to use with activated charcoal, to form less
toxic products, e.g. by means of an AOP which is integrated in the
polymer or implemented subsequent to the separation by means of the
polymer.

[0023]In particular, the method according to the invention enables
flexible use of individually dimensionally tailored molecularly imprinted
polymers for a large number of different critical harmful substances. The
thus used molecularly imprinted polymers can be regenerated and re-used.
It is also possible, instead of degradation of the not easily degradable
compound, to recover these, in particular in the case of rare compounds,
from the polymer. In total, there is consequently a large range of
possible variations and adaptations of the liquid treatment system
according to the present invention to the respective problem which is
present.

[0024]The method can be applied for the treatment of liquid media, such as
water or sewage, which is contaminated or laden with special harmful
substances. There should be mentioned, in addition to further fields, as
examples:

Industrial effluent, such as e.g. process effluent of the chemical or
pharmaceutical industry or of the paper and pulp industry, municipal
sewage, hospital sewage or treatment of partial flows thereof, and also
rehabilitation of dangerous waste and waste dumps. The method is suitable
for the treatment of sewage with a high AOX content.

[0025]The method can then be used for application in the sewage plant as a
replacement for activated charcoal or the use of ultrafiltration as final
purification.

[0026]Furthermore, the method can be applied for the treatment of harmful
substance-loaded animal excretions, e.g. working animals. Recovery of
rare chemicals which are absorbed in the selective filter component is
also conceivable.

[0027]In the following, the method for the production of molecularly
imprinted polymers (imprinting procedure of MIP) is now intended to be
described briefly. This comprises inter alia [0028]complex formation,
which is effected via specific interactions, of the target molecule
(template, print molecule) which is dissolved in a suitable solvent
(porogen) or the molecular units or functional groups thereof with the
so-called functional monomer (polymerisable unit which interacts with the
print molecule), [0029]followed by the polymerisation step together with
the crosslinker (unit with two or more cross-linking possibilities with
the functional monomers) for construction of a network of cavities of a
defined size and specific binding sites and binding patterns at defined
spacings, [0030]and finally the washing out of the template molecule.

[0031]The subject of the present invention is the use in the context of
liquid media in the environmental field, e.g. water or sewage, and with
selective removal and also degradation of the contents of these liquid
media. The selection and modification of the functional monomers or a
mixture of functional monomers, of crosslinkers or a mixture of
crosslinkers, of porogens or porogen mixtures and also of radical
starters and suitable catalytic groups for specific target molecules or
target molecule groups or the derivatives thereof and the production of a
suitable washing and purification protocol for newly produced polymers is
thereby of relevance. The invention relates, in addition to the
production of novel functional monomers, also to the method according to
the invention for selective treatment of liquids with an absorption,
washing, desorption and degradation step with the respectively used
materials and reagents or technologies, if required the method can
contain all the mentioned steps or only selected ones.

[0032]Typical functional monomers which are used (polymerisable unit which
interacts with the print molecule) can be:

carboxylic acids, such as acrylic acid, methacrylic acid,
trifluoromethacrylic acid, vinylbenzoic acid, itaconic acid, and also the
amides thereof;sulphonic acids such as acrylamidomethylpropanesulphonic
acid;heteroaromatic or weak bases, such as substituted or unsubstituted
vinylpyridines, vinylpyrimidines, vinylpyrazoles, vinylimidazoles,
vinyltriazines, vinylpurines, -indoles, -quinolines, -acridines,
-phenanthridines, bis(acrylamido)pyridine;aliphatic or aromatic vinyl
derivatives, such as substituted or unsubstituted styrenes, vinyl
naphthalenes, vinyl naphthalene carboxylic acids, vinyl naphthols, vinyl
anthracenes, vinyl anthracene carboxylic acids, vinyl phenanthrenes,
vinyl phenanthrene carboxylic acids and similar condensed aromatics,
vinyl benzamidine; acryloylamino-benzamidine, (amidinoalkyl)-styrene, the
alkyl being able to be methyl, ethyl or propyl,
N-acryloyl-(amidinoalkyl)-aniline, vinyl derivatives with chelate-forming
groups, such as iminodiacetic acid, ethylenediaminetetraacetic acid and
the like, for complexing metal ions, silanes and also mixtures of
monomers of this type. Other functional monomers can also be used.

[0033]There can serve as crosslinkers (unit with two or more cross-linking
possibilities with the functional monomers):

isomers of divinylbenzene;bis(acryloyl)-alkanes, ethane, propane and
butane being possible as alkanes;systems based on acrylic acid or
methacrylic acid, such as e.g. ethyleneglycoldimethacrylate (EDMA) and
trimethylolpropanetrimethacrylate (TRIM);tri- and tetrafunctional
acrylate crosslinkers, such as e.g. pentaerythritoltriacrylate (PETRA)
and pentaerythritoltetraacrylate (PETEA) and alsocrosslinkers which
contain functional groups, such as e.g. acrylamide units which are
cross-linked to each other on the amide nitrogens via aliphatic
(methylene- and the like), aromatic (phenylene- and the like) or
heteroaromatic (pyridinyl- and the like) spacers. Also other crosslinkers
can be used, for example also crosslinkers which are stable relative to
UV light or ozone.

[0034]There can be used as porogens (solvents which serve as solvents for
the polymerisation reaction and induce porosity in the imprinted polymer)
solvents of a different dielectric constant which influence parameters,
such as different swelling properties of the polymer, different
morphology of the polymer with various structures and pore
diameters/porosity or different binding strengths of the non-covalent
interactions, in particular aliphatic or alicyclic hydrocarbons, such as
hexane, heptane or cyclohexane;

aromatic hydrocarbons, such as toluene;halogenated hydrocarbons, such as
chloroform, dichloromethane or 1,2-dichloroethane;short-chain alcohols,
such as methanol, ethanol, propanol;ether, acetonitrile, tetrahydrofuran,
ethylacetate, acetone, dimethylformamide, dioxane,
dimethylsulphoxide;also in mixtures with each other and with water.

[0035]There can be used as initiators (radical starters)
2,2'-azobis-isobutyronitrile (AIBN),
2,2'-azobis-(2,4-dimethylvaleronitrile) (ADVN) and others, the use of UV
light is also possible.

[0036]The molecularly imprinted polymers can be present, according to the
production process, in the following forms: [0037]production of polymer
monoliths and subsequent fragmentation, [0038]a grafting of the imprinted
polymer on preformed particles, [0039]production of polymer balls from
suspension-, emulsion- or dispersion polymerisation, [0040]polymer
particles which are bonded on thin films or polymer membranes,
[0041]polymer membranes, [0042]surface-imprinted polymer phases: the
formed complexes of the template molecules with the functional monomers
bind to activated surfaces, such as e.g. silicon or glass surfaces, and
produce defined imprinted structures after washing out.

[0043]The polymer can be introduced into a separating column or into a
filter device, made of plastic material, glass, stainless steel or other
materials; or be bonded on thin films, surfaces of different materials or
polymer membranes or even be used itself as membrane. Alternatively, the
particles can be used floating freely in the liquid phase. Also other
devices can be used for absorbing the polymer.

[0044]Also a combination or successive arrangement of a plurality of
sorption steps with the same or different selective polymer materials is
conceivable. The reactor shape can also vary.

[0045]The current of the water laden with the relevant material or the
relevant material group can thus be conducted both through the separating
column, filter device, membrane etc. and be conducted almost parallel
past the sorbing material. Also other methods can be used.

[0046]A few examples of polymers which are imprinted with molecules of the
chlorophenoxy compound group are represented subsequently. These are
presented in the table in FIG. 1. This table thereby represents the
relevant substances used respectively for the production of the
molecularly imprinted polymers.

[0047]The individual components were mixed together with ice cooling in 50
ml test tubes, rinsed for 5 min. with nitrogen, sealed with parafilm and
left for 19 h at 60° C.

[0048]The polymer blocks were comminuted for processing until particles
with a particle size <250 μm were produced, thereafter they were
crushed four times with respectively 50 ml acetone and filtered
respectively via a 20 μm sieve.

[0053]FIG. 2 now shows the proportion of sorbed (in %) and concentration
of the clofibric acid remaining in the aqueous phase (in mol/l) after one
or two sorptions on respectively 300 mg of the molecularly imprinted
polymer in the MIP 1. As sewage to be treated there were used hereby 10
ml landfill leachate with the addition of 1.2*10-4M clofibric acid.
To this sewage to be treated there were added 300 mg MIP 1 and agitation
for 30 minutes was implemented.

[0054]It can be detected immediately that, even with a single sorption,
over 60% of the clofibric acid was removed from the sewage. With twofold
sorption, a sorption rate of over 80% is achieved.